Rolling mill



April 1969 E. w. BERGSTROM ETAL 3,435,648

ROLLING MILL Filed me 7, 1966 4770K Ive ys United States Patent Otfice 3,435,648 Patented Apr. 1, 1969 U.S. Cl. 72-1 6 Claims ABSTRACT OF THE DISCLOSURE An arrangement in rolling mills and the like is provided in which the rolls are mutually movable and means are provided to operate the rolls in a given relative position. Upon overload, as when foreign objects penetrate between the rolls, or when there is danger of injuries to persons, provision is made to separate the rolls in a simple and rapid manner simultaneously as their rotation is reduced or braked.'According to the invention the rolls are equipped with hydraulic cylinder and piston assemblies to keep the rolls spaced a correct relative distance apart, against springs tending to separate the rolls, with manually or automatically operated pressure release means. The release means can be directly operated by the pressure in the hydraulic system, which at overload rises or is influenced by manual means. The means for separating the rolls preferably consists of cup springs.

The features characteristic of the invention reside in that the rolling mill is equipped with means tending to separate the rolls and further means which press the rolls together against the action of the means separating them and retain the rolls at predeterminable relative distances, and that the means urging the rolls together can be made inoperative for realizing separation of the rolls by the action of a manually or automatically operable releasing device which is preferably also adapted to interrupt the power supply to the rolls and to make the braking device operative.

These and further features of the invention will appear from the following description in which reference is made to the accompanying drawing schematically illustrating an embodiment of the inventive arrangement used with a pair of rolls in a rolling mill, a calender or other machine.

One roll 1 is fixedly mounted at 3 to the frame 4 while the other roll 2 has its mounting points 5 movable in relation to the frame 4 to permit setting of the space between the rolls.

According to the invention, means tending to separate the rolls are provided between the mountings of the rolls 1 and 2. In the embodiment illustrated, the said means are cup springs 6 and 7 but it is also possible to use other similar means. Hydraulic cylinder and piston assemblies 8 and 9 are disposed at the mountings of the movable roll 2 to counteract the separating effect of the cup springs 6 and 7. Upon supply of pressure fiuid, the cylinder and piston assemblies urge the movable roll 2 against the fixed roll, and by regulation of the pressure acting on the cylinder and piston assemblies the roll 2 can be set at the desired distance from the roll 1. A pump unit 10 is associated with both cylinder and piston assemblies 8 and 9 over conduits 11 and 12. The pump unit is adapted to deliver a large amount of fluid at a moderate pressure and to shift the movable roll 2 from its extreme position close to the fixed roll 1. The final adjustment of the movable roll 2 is then realized with the aid of the preferably manually operated adjusting pumps 13 and 14 inserted in the conduits 11 and 12 and adapted to deliver a small amount of fluid at a high pressure. Of course, the adjusting pumps 13 and 14 may be power operated. Also disposed in the conduits 11 and 12 are valve means 15 and 16 of check valve type so adapted as to enclose the fluid amounts acting upon the cylinder and piston assemblies 8 and 9, whereby the movable roll 2 is maintained at the desired distance from the fixed roll 1 under the desired pressure application.

The rolling mill is also equipped with a braking device 17. In the embodiment illustrated, the braking device is associated with the shaft 18 which connects a motor (not shown) with the transmission mechanism (not shown) of the rolls. The braking device is so adapted that its brake shoes are pressed against the brake disk 19 by means of cup springs 30. The action of these springs is counteracted by a hydraulic cylinder and piston assembly 20 which is associated, via the conduit 21, with the pump unit 10 common to the cylinder and piston assemblies 8 and 9 actuating the roll 2. The hydraulic pressure acting upon the cylinder and piston assembly of the brake thus tends to move the brake shoes away from the brake disk 19.

Each of the conduits 11, 12 and 21 extending from the hydraulic pump 10 are provided ahead of the respective cylinder and piston assemblies 8, 9 and 20 with branch lines or return lines 22, 23 and 24 which are equipped with valves 25, 26 and 27. These valves are adapted in the normal operation of the rolling mill to close the return lines so that the hydraulic pressure acts upon the respective cylinder and piston assembly. The supply conduits 11 and 12 to the cylinder and piston assemblies acting upon the roll 2 have pressure sensing means 28 and 29 connected therein, which sense the pressure in the lines connected to the cylinder and piston assemblies 8 and 9 and also the pressure between the rolls since the pressure in the lines connected to the cylinder and piston assemblies is directly proportional to that between the rolls.

Adjustment of the valves 25, 26 and 27 will open the passages to the return lines 22, 23 and 24, the pressure acting upon the cylinder and piston assemblies rapidly diminishing. As a result, the springs 6 and 7 between the rolls 1 and 2 rapidly separate the rolls since the force urging the rolls together ceases, and the braking device is made operative because the force counteracting the springs thereof likewise ceases. Actuation of the valves is primarily intended to be brought about by means of an emergency stop device which may be a rope, gate or like means operating a switch. Of course, the emergency stop device is also suitably arranged so as to simultaneously stop the drive motor or interrupt the power connection between it and the rolls. The valves 25, 26 and 27 can also be caused to open at an overload of the rolling mill in that the pressure sensing means 28 and 29 sensing the pressures in the cylinder and piston assemblies 8 and 9, which pressures are directly dependent upon the load of the rolls, will then deliver an impulse to the switch which in turn interrupts the supply of power, makes the brake operative and separates the rolls from one another. Overloading occurs for example when too much or too hard a material is fed between the rolls but it may also arise when foreign articles penetrate between them. The pressure sensing means may finally also be so adapted as to render the emergency stop device operative when the movable roll 2, by reason of different pressure conditions in the two cylinder and piston assemblies 8 and 9, is moved out of the position in which it is parallel to the fixed roll 1.

As alread mentioned, the rolls can be rapidly returned after an emergency stop to operative position by means of the pump unit 10 common to them, whereupon adjust- 3 ment of the rolls is performed with the aid of the adjusting pumps 13 and 14. Naturally, in lieu of the two adjusting pumps 13 and 14, a single resetting pump may be provided, and in addition the hydraulic system may be provided with other means for controlling or regulating the position of the movable roll.

While the invention has been described in an embodiment illustrated in the drawing, it is understood by those skilled in the art that it may be modified in several ways within the scope of the appended claims.

What we claim and desire to secure b Letters Patent is:

1. In a rolling mill having a pair of rotatively driven parallel rolls resiliently biased apart with variable hydraulic actuation against the biasing force at each end of one roll to provide compressive force between the rolls and in which automatic quick-response arresting of the rotation is effected upon encountering excessive resistance to compression between said rolls, apparatus comprising:

a pump source of hydraulic fluid under pressure including a branched conduit,

pressure-responsive motor means coupled to two branches of said conduit for forcing each end of one said roll toward a corresponding end of the other said roll,

check valve means for preventing back flow of said fluid toward said source,

pressure-boosting means individual to each of said two branches for increasing the pressure therein to control pressure at the nip of rolls,

pressure-sensing means for providing an actuating signal in response to pressure increase in each of said two branches beyond a predetermined limit,

fast-operating relief valve means in each said branch hydraulic means connected to a third said branch for overcoming normal braking bias when pressure in said two branches is not released.

2. In a rolling mill according to claim 1, conduit means connecting said relief valve means to said source for return thereto of fluid released.

3. In a rolling mill according to claim 1, said braking means including an actuatable pressure relief valve in said third branch operative to release said fluid from said third branch upon occurrence of an actuation signal.

4. In a rolling mill according to claim 3, said pressure relief valve and relief valve means being operative in response to pressure exceeding said predetermined limit at either end of said rolls.

5. In a rolling mill according to claim 3, conduit means connecting said relief valve and relief valve means to said source for automatic return of hydraulic fluid to said source whereby operation of the mill may be resumed in response to removal of said actuating signal.

6. In a rolling mill according to claim 1, at least some of said biasing means being cup springs means for exerting relatively large biasing forces over relatively short displacements.

References Cited UNITED STATES PATENTS 1,477,840 12/1923 Mortensen 18--2 2,182,900 12/1938 McIlvired 18-2 2,205,632 6/1940 Schwartz et al. 721 2,382,263 8/1945 Schnell 188-170 2,699,196 1/ 1955 Cozzo 721 3,055,243 9/1962 Cauley et a1. 72-4 3,327,510 6/ 1967 Diolot 72245 FOREIGN PATENTS 1,124,811 10/ 1956 France.

CHARLES W. LANHAM, Primary Examiner.

A. RUDERMAN, Assistant Examiner.

U.S. Cl. X.R. 

